Proton vs. Photon Radiation Therapy for Primary Gliomas: An Analysis of the National Cancer Data Base

• Authors: Jaymin Jhaveri, Emory University; En Cheng, Emory University; Sibo Tian, Emory University; Zachary Buchwald, Emory University; Mudit Chowdhary, Rush University; Yuan Liu, Emory University; Theresa Gillespie, Emory University; Jeffrey Olson, Emory University; Aidnag z. Diaz, Rush University; Alfredo Voloschin, Emory University; Bree Eaton, Emory University; Ian Crocker, Emory University; Mark McDonald, Emory University; Walter Curran, Emory University; Kirtesh Patel, Emory University
• Journal Title: Frontiers in Oncology
• Volume: Volume 8
• Publisher: Frontiers Media | 2018-11-28, Pages 440-440
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.3389/fonc.2018.00440
• Subjects: Health Sciences, Oncology; Biology, Radiation
• Keywords: Science & Technology; Life Sciences & Biomedicine; Oncology; proton therapy; gliomas; overall survival; IMRT; NCDB; LOW-GRADE GLIOMA; PROGNOSTIC-FACTORS; VINCRISTINE CHEMOTHERAPY; ADJUVANT PROCARBAZINE; LOMUSTINE; ADULTS; TUMORS; BRAIN; RADIOTHERAPY; BENEFIT

Abstract

Background: To investigate the impact of proton radiotherapy (PBT) on overall survival (OS) and evaluate PBT usage trends for patients with gliomas in the National Cancer Data Base (NCDB). Methods: Patients with a diagnosis of World Health Organization (WHO) Grade I-IV glioma treated with definitive radiation therapy (RT) between the years of 2004-13 were identified. Patients were stratified based on WHO Grade and photon radiotherapy (XRT) vs. PBT. Univariate (UVA) and multivariable analysis (MVA) with OS were performed by Cox proportional hazards model and log-rank tests. Propensity score (PS) weighting was utilized to account for differences in patient characteristics and to minimize selection bias. Results: There were a total of 49,405 patients treated with XRT and 170 patients treated with PBT. Median follow-up time was 62.1 months. On MVA, the following factors were associated with receipt of PBT (all p < 0.05): WHO Grade I-II gliomas, treatment at an academic/research program, west geographic facility location, and surgical resection. After PS weighting, all patients treated with PBT were found to have superior median and 5 year survival than patients treated with XRT: 45.9 vs. 29.7 months (p = 0.009) and 46.1 vs. 35.5% (p = 0.0160), respectively. Conclusions: PBT is associated with improved OS compared to XRT for patients with gliomas. This finding warrants verification in the randomized trial setting in order to account for potential patient imbalances not adequately captured by the NCDB, such as tumor molecular characteristics and patient performance status. Importance of the Study: This is the first study that compares the outcomes of patients treated with photon based radiotherapy vs. proton based radiotherapy for patients with gliomas. In this retrospective analysis, the results demonstrate that proton therapy is associated with improved outcomes which support ongoing prospective, randomized clinical trials comparing the two modalities in patients with gliomas.